New to the scene so bare with me...

I just found out that my 90' has had the pre cats cut off and straight pipe put in its place. Are there any problems with this? I live in Oklahoma and we have no state inspection. Is there a power gain from this or did the previous screw me over?

I also suspect that I have a leaking injector and my intake manifold gasket is leaking. Any advice on a good upgrade combo while I have the top half of the motor apart. Not wanting to go to radical, just warm it over a bit. It is completely stock as far as I can tell and has 73,xxx miles. Thanks for the help and advice...

 

well it is against the law to mess with emission equipment, BUT if you don't have state inspections, do you have emissions testing? and yeah without the pre cats you should have less back pressure.
while you the pelnum off and runners you could port them, got a good dremill tool!! no cost just a little work. you can lay the gasket on the runner ports mark in and grind away, same were the throttle body bolts to pelnum and the inside of pelnum right behind the throttle body.

 

Actually replacing your stock front Y and stock cat with a pre-catless Y and a 3-stage cat is 48-states legal.

Yes that mod is a performance enhancing move.

 

your car should pass an emmision test without the pre-cats, the 3-way single converter works fine. 84 and 85 vettes didn't come with the pre-cats, GM started putting them in 86 and later.

 

If law requires and it makes you feel better then just buy the front y-pipe with pre-cats and have it installed. either way it's not going to make the car go all that much faster. I wouldn't change the engine too much these cars run fine stock, when they're tuned properly.

 

Working over the intake always helps IF you upgrade the exhaust also. Some like to upgrade to a 2.5" Y, 3-3 1/2" main and a good muffler.
To spend money on the intake and nothing else is a waste.





If you aren't worried about emissions, leave the precats out. Once you get injectors replaced, put a high quality main cat in.

 

WOW there are ALOT of folks who feel quite differently
if my nuts were squashed in a vice, i suppose i'd feel the same

 

Brad, sometimes you have a way with words

 

Let go of them then

 

 

BTW, to freshen it up:
-do the TB collant bypass & MAT relocation mods (1)
-toss the frisbee from the front of the water pump pulley
-install a 160deg T-stat & fan switch
-cut the air filter lid and install a K&N filter

Note (1) These mods won't add noticible power but will make working around the plenum much easier next time.

Instead of just cutting out the pre cats you would gain more by replacing them with two high flow cats and inserting a 3" pipe in place of the main cat. Keep the OEM main cat around in case you need to do emissions checks later.

 

www.performancepeddler.com
Talk to Brad, first class service.

They have a nice 2.5" aluminized front Y with magnaflow precats. I believe they are mandrel bent, also. Very reasonable.